Human Placenta as a Source of Neuroendocrine Factors

Abstract

Progress in the understanding of the physiological and pathological functions of the placenta introduced the concept that the placenta is a neuroendocrine organ, since it shows local production and release of substances analog to neurohormones. These products act as endocrine, paracrine and autocrine factors to control the secretion of other regulatory molecules, including the pituitary hormones of both mother and fetus and their placental counterparts. Furthermore, they may play a role in the regulation of maternal and fetal physiology during pregnancy, ranging from the control of placental anchoring to fetal growth and maturation, fine regulation of uterine blood flow and/or initiation of labor. All this evidence underlines the decisive contribution of the placenta to all phases of gestation, through a range of substances largely exceeding the classically known sex steroids and chorionic gonadotropin, throughout normal pregnancy as well as in the presence of gestational diseases.

Measurement of Androgen and Estrogen Concentrations in Cord Blood: Accuracy, Biological Interpretation, and Applications to Understanding Human Behavioral Development

“…The placenta is also a very active metabolic organ with respect to phase II metabolism (conjugation). While steroids are lipophilic and cross the placenta in both directions, most of them are metabolized by the placenta en route (20). Fetal blood leaves the placenta (enriched with placental steroid metabolites and some maternal steroids) via the umbilical vein (UV) and returns from the fetus to the placenta via the umbilical artery [UA; (21)].…”

Myometrial contractility influences oxytocin receptor (OXTR) expression in term trophoblast cells obtained from the maternal surface of the human placenta

“…Outside the brain, synthesis of mRNA encoding OXT was demonstrated in many human tissues, including intrauterine tissues in advanced gestation, principally in the decidua but also in the placental membranes (chorion, amnion) [ 14 , 15 ]. These findings may lead to suggestion that paracrine or autocrine role rather than, or in addition to, an endocrine role of OXT should be expected in respect of contractile activity of the human uterus [ 16 , 17 ]. So if OXT is not considered solely as an endorine factor, many previous conclusions about its effect on the course of subsequent stages of pregnancy and labor should be retested [ 6 ].…”

Placenta – Worth Trying? Human Maternal Placentophagy: Possible Benefit and Potential Risks

“…The physiological role of the placenta during pregnancy is extremely complex: metabolism, excretion, respiration and immunological processes such as hormone synthesis ensure and regulate the survival and growth of the fetus and the adaptation of the motherʼs body to pregnancy and childbirth. Hormones such as oxytocin, human placental lactogen, progesterone, oestrogens and neurohormones such as thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH) and corticotropin-releasing hormone (CRH), some of them are produced exponentially during pregnancy 3 . The hormonal activity of the fetoplacental unit at the end of pregnancy can be summarised as follows: The production of fetal cortisol stimulates placental CRH secretion.…”

“…Die physiologische Funktion der Plazenta während der Schwangerschaft ist überaus komplex: Stoffwechsel, Ausscheidung, Atmung, immunologische Vorgänge sowie Hormonsynthese sichern und regulieren das Überleben und Wachstum des Feten und die Adaptation des maternalen Organismus auf Schwangerschaft und Geburt. Dabei werden im Verlauf der Schwangerschaft teilweise in exponentiellem Ausmaß Hormone wie Oxytocin, humanes Plazentalaktogen, Progesteron, Östrogene und Neurohormone wie thyreoideastimulierendes Hormon (TSH), adrenokortikotropes Hormon (ACTH) und Corticotropin-releasing Hormone (CRH) von der Plazenta produziert 3 . Die hormonelle Aktivität der fetoplazentaren Einheit am Ende der Schwangerschaft kann folgendermaßen zusammengefasst werden: Die Produktion von fetalem Kortisol ist Stimulans für eine plazentare CRH-Sekretion.…”